Process and device for photographing microscopic objects

ABSTRACT

A process for photographing microscopic objects with consideration of exposure time values to be determined and for making visible a spatially variable measurement spot and an exposure format making before and after the exposure is indicated, which process proceeds according to the process steps which are prescribed in accordance with the claims. In addition to this, a microphotographic device for carrying out the process or processes, having a microscope tube with return mirror device and a photographic eyepiece, downstream of which there are disposed a device for measuring the brightness of an object detail as well as markings to make visible at least one detail measurement field and the image field of a camera in the observation beam path, the detail measurement field being adjustably constructed in the functional plane, which is a plane conjugate with the eyepiece intermediate image, in the region associated with the entire image field, and the detail measurement diaphragm being disposed in a first illumination beam path, as well as a carrier containing the image field marking being disposed in a second illumination beam path, and a first beam splitter combining the two illumination partial beam paths being provided, and a second beam splitter being disposed between the camera shutter and the eyepiece optical system of the microscope, in such a manner that the images, transmitted by the combined illumiation partial beam paths, of the detail measurement diaphragm and of the image field marking are reflected into the eyepiece intermediate image plane in a superposed manner, is described, graphically represented and claimed.

The invention relates to a process for selective photography withshortened and stored exposure time values or with exposure time valuescorrected during the exposure process, a measurement spot of variablespatial location as well as exposure field markings being made visiblebefore and after the exposure, as well as to a device for carrying outthis process.

German Patent Specification No. 2,619,853 discloses a microphotographicdevice as an attachment camera for microscopes, which permits anexposure correction during the exposure process by means of a fixedlybuilt-in 50/50 neutral beam splitter. In this case, it isdisadvantageous that the beam splitter fixedly disposed in thephotographic beam path consumes 50% of the available quantity of lightfor the exposure control. As a result of this, only 50% of the lightpasses to the film. As a consequence of this, the exposure times arelengthened by the factor "two". This circumstance has a verydisadvantageous effect, especially when--as is customary with specialmicroscopy processes--objects of very low light intensity are to beobserved and recorded.

It is therefore the object of the present invention to overcome thedisadvantages of known microphotographic devices and processes and toprovide a process as well as a device, with which process or with whichdevice a great gain in time can be achieved, especially whenlarge-format camera attachments are employed, and moreover there is anexpansion of the photographic recording possibilities, especially ofminiature fluorescence exposures with reduced exposure times, which areotherwise no longer possible, in consequence of object destruction withthe formerly customary long times. A further partial object consists infurthermore obtaining the advantage of the exposure correction duringthe exposure for a series of practical cases of application withfluorescence exposures by the selection of the exposure program, i.e. incombining both photography with shortened exposure times and also theselective exposure correction during the exposure.

With a process of the initially mentioned type, this object is achieved,according to the invention, by the features of claim 1, as well as ineach instance alternatively by claims 2, 3 or 4. Further refinements areevident from the process claims 5 to 8. The object is furthermoreachieved by a device for carrying out the initially mentioned processesaccording to claim 9; further refinements are evident from the deviceclaims 10 to 14.

An embodiment of the invention is diagrammatically represented in thedrawing.

The photographic beam path 16 proceeds from an object 6 to be examinedand extends along the optical microscope axis 26 via a photographiceyepiece 19, a beam splitter system 1 and a shutter 20 to the imageexposure plane 18, in which, for example, a film can be positioned.

The observation beam path 13 likewise proceeds from the object 6 and isdeflected at a splitter surface of a splitter prism disposed in theoptical microscope axis 26 into the microscope eyepiece 5, where itpasses to the observer 27. A dark flap 12 can, in the working position,keep extraneous light on the observer side away, in the case ofspecified program functions.

An illumination partial beam path 14 proceeds from a lamp 8, whichillumination partial beam path, after passing through a format reticule3, which moreover exhibits a sharpness cross, and after deflection at anappropriate optical component, onto a 50/50 beam splitter 25, where itit recombined with a further illumination partial beam path 15. Theillumination partial beam path 15 likewise proceeds from the lamp 8 and,after two-fold deflection, impinges on a full mirror, which is disposedin the measurement beam path 10 so as to be slidable out and which canbe designed also as a rotary mirror 11, and falls from there through astationary integral measurement diaphragm 23 as well as a detailmeasurement diaphgram carrier 7, which is disposed immediatelytherebehind so as to be slidable out and which is held within its planeso as to be spatially variable, onto the already mentioned beam splitter25, from which the combined illumination beam path 14 15 impinges on thebeam splitter system 1. In the case represented, the glass cube 1a issituated in the working position, i.e. in the optical microscope axis26. This glass cube 1a possesses a fullmirror-coated diagonal surface,which stands in a 45° position in relation to the vertical opticalmicroscope axis 26 and to the combined illumination beam path 14, 15.

The beam splitter cube 1c disposed beside the glass cube 1a exhibits abeam splitter surface in the diagonal position, which exhibits adiscrete transmission/reflection ratio between 95/5 and99.5/0.5--preferably 99/1.

The beam splitter cube 1b exhibits a splitter surface in the diagonalposition, which exhibits a transmission/reflection ratio of 50/50. Itshould be emphasized that use can be made, in addition or alternativelyto the indicated beam splitter tubes, also of those which exhibit otherphysical or geometric beam splitting properties. The adjustment of thebeam splitter system 1 takes place by motor.

The measurement beam path 10 proceeds from the beam splitter system 1,more precisely from the glass cube 1a situated in the working positionin the drawing, and is thrown, after deflection at the beam splitter 25when the full mirror (or rotary mirror 11) is swung out, onto the lightreceiver 21. The rotary mirror 11, which is shown as a flap mirror whichcan be moved out in the graphical representation, is moved by motorunder program control and possesses a labyrinth, which, in the workingposition, closes off the light receiver 21 in a light-tight manner. Thisbrings advantages for the dark-current compensation. Thus, for examplewith known microphotographic devices, it is only possible to achieve adark-current compensation if use is made of a photographic tube whichcontains a slider setting in which no light can pass to thelight-measuring device.

The dark flap 9 which is pivotable into the beam path 15 by motor underprogram control has two functions. In the case of integral measurement,the dark flap 9 is switched into the working position for theobservation of the image, in order to prevent the integral measurementdiaphgram 23 from being illuminated from behind. Otherwise, this wouldbe superposed, in its entire magnitude, on the object image. The secondfunction consists in that it remains switched on in the case of eachlight measurement. By this means, scattered light from the ventilationsystem of the lamp house is prevented from being superposed on themeasurement light and falsifying the measurement.

The change between integral measurement and detail measurement takesplace in the device according to the invention or the correspondingprocesses in such a manner that the integral measurement diaphragm 13always remains fixed in its position. For a spot measurement, thespatially variable partial measurement diaphgram 24 or its carrier 7 isswitched, for example by means of a lifting magnet, closely in front ofthe integral measurement diaphragm 23 by key pressure from the controlunit 28. A gray filter (1%), which was formerly customary with a knownmicrophotographic process and which adapted the transmission of theintegral measurement diaphragm to the transmission of the detailmeasurement diaphragm, can be dispensed with in the case of the presentinvention, since, in place of this, a beam splitter cube 1c can be runinto the working position. The detail measurement diaphragm carrier 7 ismounted, for example, by a lifting magnet on a carriage, which isoperated by means of two electric motors from the control unit 28.

The markings for exposure fields on the format reticule 3 can be appliedon a movable mask, which is adapted to a spherical-shell surface, whichcorresponds to the curvature of the image field. By this means, theimage sharpness of the markings remains preserved over the entire field.

If required, a color temperature measurement beam path 17 can beconstructed. The color temperature measurement is introduced by pushingthe deflecting mirror 29 into the measurement beam path 10. The mirror29 situated in the working position is registered, for example, by areflex light barrier, which on its part switches over the control unit28 to color temperature measurement. The measured color temperatureappears in the display of the control unit 28, in place of the otherwisedisplayed film speed.

The control unit 28 is shown purely diagrammatically in the figure withthe associated exposure control system 2 and the release key 22. Thearrows illustrate the functional links to the individual opto-mechanicalcomponents.

In place of a color temperature measurement attachment, a computer flashsensor with a housing can also be fitted by means of the deflectingmirror 29. The position of the mirror 29 is recorded, again, by a reflexlight barrier. An appropriate opto-electronic coupling leads, in thecontrol unit 28, to an automatic flash readiness; in this case, whenthis function is operative switching takes place automatically tointegral measurement.

The high transmission/reflection ratio of, for example, 99/1 of thesplitter surface of the beam splitter cube 1c is achieved by thedifference in refractive index between glass and cement layer of thepertinent component. The beam splitter system 1 is moved by motor underprogram control, and is positioned by fork light barriers, which are notshown.

We claim:
 1. A process for photographing microscopic objects withconsideration of exposure time values to be determined as well as formaking visible a spatial variable measurement spot and an exposureformat marking before and after the exposure, wherein a beam splittersystem (1), which is disposed so as to be transversely displaceable inthe photographic beam path (16) and which exhibits splitter surfaces ofdiffereing transmission/reflection ratios (1b;1c) and, in addition, afull-mirror-coating surface (1a), a rotary mirror (11) disposed in themeasurement beam path (10) in front of the light receiver (21) as wellas a dark flap (9) disposed in the illumination beam path (15) aredriven and positioned, in order to produce microphotographic exposureswith shortened and stored exposure times, with execution of a spotmeasurement, by means of the spatially variable measurement spot,according to the following process steps:(a) the beam splitter system(1) is positioned in the optical microscope axis (26) in such a mannerthat the full-mirror-coating surface of the glass cube (1a) in thediagonal position deflects the illumination beam paths (14 and 15respectively) via the photographic eyepiece (19) into the microscopeeyepiece (5); (b) after setting of the image sharpness, selection of theimage section of the object (6) and positioning of the spatiallyvariable detail measurement diaphragm (24) by the observer (27) in theworking position, there takes place an (c) actuation of a release key(22) on a control unit (28), whereby the following functions areinitiated:(c1) a lamp (8) is extinguished; (c2) a dark flap (9) pivotsinto the illumination beam path (15); (c3) the rotary mirror (11) pivotsout of the measurement beam path (10); (c4) a dark flap (12) in theobservation beam path (13) swings into the working position; (c5) thelight receiver (21) measures the light falling through the detailmeasurement diaphragm (24), and the value measured by the light receiver(21) is then passed to an exposure control system (2) and stored; (c6)the beam splitter system (1) is now positioned in such a manner that thebeam splitter cube (1c) passes with that splitter surface in thediagonal position transversely to the optical microscope axis (26) whichexhibits a transmission/reflection ratio of 99/1; (c7) the exposurecontrol system (2) opens the shutter (20), depending upon therespectively stored value, for an exposure of an image recording mediumdisposed in the plane (18), for example a film; (c8) followingcompletion of exposure and blocking of the shutter (20) for the furtherpassage of the photographic beam path (16), the beam splitter system (1)is again guided back into the initial position--i.e. the glass cube (1a)in the working position--the lamp (8) being simultaneously switched on,the dark flaps (9 and 12, respectively) being switched out, the rotarymirror (11) being pivoted into the measurement beam path (10), and theimage recording medium being further transported.
 2. The process asclaimed in claim 1, wherein the temporal sequence of the partial processsteps (c1) to (c4) is a sequence selectable at will.
 3. The process asclaimed in claim 1, wherein, in addition, a color temperaturemeasurement takes place by insertion of a deflecting mirror (29) intothe measurement beam path (10), the color temperature measurement beam(17) thereby branched off being divided, after passing through an imagesplitting element, for example a line or prism raster (30), into twopartial beams (17a;17b), in such a manner that the partial beam (17a)after passing through a blue filter (31) and the partial beam (17b)after passing through a red filter (32) each fall on a respective lightreceiver (33, and 34, respectively), for example silicon diodes.
 4. Theprocess as claimed in claim 1, wherein, in addition, a computer flashdevice is optically coupled to the total system by insertion of adeflecting mirror (29) into the measurement beam path, themicrophotographic functions being automatically switched to integralmeasurement and a flash readiness being automatically produced in thecontrol unit (28).
 5. A microphotographic device for carrying out theprocess as claimed in claim 1, having a microscope tube with returnmirror device and a photographic eyepiece, downstream of which there aredisposed a device for measuring the brightness of an object detail aswell as markings to make visible at least one detail measurement fieldand the image field of a camera in the observation beam path, the detailmeasurement field being constructed adjustably in the functional plane,which is a plane conjugate with the eyepiece intermediate image, in theregion associated with the entire image field, and the detailmeasurement diaphragm being disposed in a first illumination beam path,as well as a carrier containing the image field marking being disposedin a second illumination beam path, a first beam splitter combining thetwo illumination partial beam paths being provided, and second beamsplitter being disposed between the camera shutter and the eyepieceoptical system of the microscope, in such a manner that the images,transferred by the combined illumination partial beam paths, of thedetail measurement diaphragm and of the image field marking arereflected into the eyepiece intermediate image plane in a superposedmanner, wherein, in place of the second beam splitter, a beam splittersystem (1) is disposed in the optical microscope axis (26) so as to betransversely displaceable in relation to the latter, the beam splittersystem (1), which is positionable by motor, including at least two beamdeflection elements (1a,1b and 1a,1c, respectively), one of which is aglass cube (1a) with a diagonal full-mirror-coating surface and theother is a beam splitter cube (1c) with a diagonal splitter-mirrorsurface (1b) having a transmission/reflection ratio 50/50 or with adiagonal splitter-mirror surface (1c) having a transmission/reflectionratio >1, and a dark flap (9) which can be pivoted in and out beingdisposed in the illumination beam path (15) for the detail measurementdiaphragm (24) between the lamp (8) and a full-mirror-coated rotarymirror (11) which can be introduced into the measurment beam path (10).6. The device as claimed in claim 5, wherein the beam splitter cube (1c)exhibits a discrete transmission/reflection ratio between 95/5 and99.5/0.5--preferably 99/1.
 7. The device as claimed in claim 5, whereinthe beam splitter system (1) exhibits, in addition to the glass cube(1a) with a diagonal full-mirror-coating surface, at least two beamsplitter cubes with discrete transmission/reflection ratios >1.
 8. Thedevice as claimed in claim 5, wherein the beam splitters exhibit neutraland/or dichromatic splitter surfaces.
 9. The device as claimed in claim5, wherein, in addition, a deflecting mirror (29) which can beintroduced into the measurement beam path (10) is provided, from which acolor temperature measurement beam path (17) proceeds, which, afterpassing through a raster (30), is split up into two partial beams (17a,17b), which, after passing through a blue filter or a red filter,respectively (31 and 32, respectively), impinge on respective lightreceivers (33 and 34, respectively).
 10. The device as claimed in claim5, wherein, in order to achieve a transmission/reflection ratio of thesplitter-mirror surface of the beam splitter cube (1c) between 95/5 and99.5/0.5, a respective discrete difference exists between the refractiveindex of the prism material and that of the cement layer material of thebeam splitter cube (1c).
 11. A process for photographing microscopicobjects with consideration of exposure time values to be determined, aswell as for making visible an exposure format marking before and afterthe exposure, wherein a beam splitter system (1), which is disposed soas to be transversely displaceable in the photographic beam path (16)and which exhibits splitter surfaces of differingtransmission/reflection ratios (1b;1c) and, in addition, afull-mirror-coating surface (1a), a rotary mirror (11) disposed in themeasurement beam path (10) in front of the light receiver (21), as wellas a dark flap (9) disposed in the illumination beam path (15) aredriven and positioned, to produce microphotographic exposures withshortened and corrected exposure times, with the execution of anexposure correction, with integral measurement, according to thefollowing process steps:(a) the beam splitter system (1) is positionedin the optical microscope axis (26) in such a manner that thefull-mirror-coating surface of the glass cube (1a) in the diagonalposition deflects the illumination beam path (14) via the photographiceyepiece (19) into the microscope eyepiece (5); (b) after setting of theimage sharpness and selection of the image section of the object (6) bythe observer (27), there takes place an (c) actuation of a release key(22) on a control unit (28), whereby the following functions areinitiated:(c1) with the back flap (9) left in the illumination beam path(15), a lamp (8) is extinguished; (c2) the rotary mirror (11) is pivotedout of the measurement beam path (10); (c3) the detail measurementdiaphragm carrier (7) is pivoted out of the measurement beam path (10);(c4) a dark flap (12) is introduced into the observation beam path (13);(c5) the beam splitter system (1) is now positioned in such a mannerthat the beam splitter cube (1c) passes with that splitter surface inthe diagonal position in relation to the optical microscope axis (26)which exhibits a transmission/reflection ratio of 99/1; (c6) the lightreceiver (21) measures the light falling through a stationary integralmeasurement diaphragm (23), which is released by displacement of thecarrier (7) exhibiting the detail measurement diaphragm (24), out of themeasurement beam path (10), and the measured value is then passed to anexposure control system (2) and stored; (c7) the exposure control system(2) opens the shutter (20), depending upon the respectively measuredvalue, for an exposure of an image recording medium disposed in theplane (18), for example a film, the exposure measurement taking placeduring the exposure process and, in the case of varying objectbrightnesses, an appropriate correction of the exposure time beingsimultaneously undertaken, (c8) following completion of exposure andblocking of the shutter (20) for the further passage of the photographicbeam path (16), the beam splitter system (1) is again guided back intothe initial position--the glass cube (1a) therefore in the workingposition--at the same time the lamp (8) being switched on, the rotarymirror (11) being pivoted into the measurement beam path (10), the darkflap (12) being switched out, and the image recording medium beingfurther transported.
 12. The process as claimed in claim 11, wherein thetemporal sequence of the respective partial process steps (c1) to (c5)is a sequence selectable at will.
 13. A process for photographingmicroscopic objects with consideration of exposure time values to bedetermined, as well as for making visible a spatially variablemeasurement spot and an exposure format marking before and after theexposure, wherein a beam splitter system (1), which is disposed so as tobe transversely displaceable in the photographic beam path (16) andwhich exhibits splitter surfaces of differing transmission/reflectionratios (1b;1c) and, in addition, a full-mirror-coating surface (1a), arotary mirror (11) disposed in the measurement beam path (10) in frontof the light receiver (21), as well as a dark flap (9) disposed in theillumination beam path (15) are driven and positioned, to producemicrophotographic exposures with corrected exposure times, with theexecution of a spot measurement, by means of the spatially variablemeasurement spot, according to the following process steps:(a) the beamsplitter system (1) is positioned in the optical microscope axis (26) insuch a manner that the glass cube (1a) with full mirror in the diagonalposition deflects the illumination beam paths (14 and 15) via thephotographic eyepiece (19) into the microscope eyepiece (5); (b) aftersetting of the image sharpness and selection of the image section of theobject (6) by the observer (27), the spatially variable detailmeasurement diaphragm (24) is illuminated rearwards, with the dark flamp(9) swung out of the illumination beam path (15), and is brought intocoincidence with a position of the object (6) which is representative ofa correct exposure; (c) thereafter, a release key (22) on a control unit(28) is actuated, whereby the following functions are initiated:(c1) alamp (8) is extinguished; (c2) the dark flap (9) pivots into theillumination beam path (15); (c3) the rotary mirror (11) is pivoted outof the measurement beam path (10); (c4) a dark flap (12) is introducedinto the observation beam path (13); (c5) the beam splitter system (1)is now positioned in such a manner that the beam splitter cube (1b)passes with that splitter surface in the diagonal position in relationto the optical microscope axis (26) which exhibits atransmission/reflection ratio of 50/50; (c6) the light receiver (21)measures the incident light and the measured value is then passed to anexposure control system (2), and <(c7) the exposure control system (2)opens the shutter (20), with consideration of the measured quantity oflight, for an exposure of an image recording medium disposed in theplane (18), for example a film, occurring changes in the brightness ofthe object (6) being corrected; (c8) following completion of exposureand blocking of the shutter (20) for the further passage of thephotographic beam path (16), the beam splitter system (1) is againguided back into the initial position--the glass cube (1a) therefore inthe working position--the lamp (8) being simultaneously switched on, therotary mirror (11) being pivoted into the measurement beam path (10),the dark flaps (9 and 12 respectively) being switched out, and the imagerecording medium being further transported.
 14. The process as claimedin claim 13, wherein the temporal sequence of the respective partialprocess steps (c1) to (c5) is a sequence selectable at will.
 15. Aprocess for photographing microscopic objects, with consideration ofexposure time values to be determined, as well as for making visible aspatially variable measurement spot and an exposure format markingbefore and after the exposure, wherein a beam splitter system (1), whichis disposed so as to be transversely displaceable in the photographicbeam path (16) and which exhibits a beam splitter cube (1c) with asplitter layer having a discrete transmission/reflection ratio withinthe range between 95/5 and 99.5/0.5, and, in addition, a glass cubehaving a full-mirror-coating surface (1a), a rotary mirror (11) disposedin the measurement beam path (10) in front of the light receiver (21),as well as a dark flap (9) disposed in the illumination beam path (15),are driven and positioned, to produce microphotographic exposures withshortened and corrected exposure times, with the execution of a spotmeasurement, by means of the spatially variable measurement spot,according to the following process steps:(a) the beam splitter system(1) is positioned in the optical microscope axis (26) in such a mannerthat the full-mirror-coating surface of the cube (1a) in the diagonalposition deflects the illumination beam paths (14 and 15, respectively)via the photograhic eyepiece (19) into the microscope eyepiece (5); (b)after setting of the image sharpness, selection of the image section ofthe object (6) and positioning of the spatially variable detailmeasurement diaphragm (24) by the observer (27) in the working position,there takes place an (c) actuation of the release key (22) on a controlunit (28), whereby the following functions are initiated:(c1) the lamp(8) is extinguished; (c2) the dark flap (9) pivots into the illuminationbeam path (15); (c3) the rotary mirror (11) pivots out of themeasurement beam path (10); (c4) the dark flap (12) in the observationbeam path (13) swings into the working position; (c5) the light receiver(21) measures the light falling through the detail measurement diaphragm(24), and the value measured by the light receiver (21) is then passedto an exposure control system (2) and stored; (c6) the beam splittersystem (1) is now positioned in such a manner that the beam splittercube (1c) passes into the diagonal position in relation to the opticalmicroscope axis (26); (c7) the detail measurement diaphragm carrier (7)with the detail measurement diaphragm (24) pivots out of the measurementbeam path (15); (c8) the light receiver (21) measures the light fallingthrough the integral measurement diaphragm (23), the value measured bythe light receiver (21) is again passed to the exposure control system(2), which then associates with the just measured value such an exposuretime which corresponds to that time which was determined according tothe partial step (c5); (c9) the exposure control system (2) opens theshutter (20) for an exposure of an image recording medium disposed inthe plane (18), for example a film, the exposure measurement takingplace during the exposure process and, with varying object brightnesses,an appropriate correction of the exposure time being simultaneouslyundertaken; (c10) following completion of exposure and blocking of theshutter (20) for the further passage of the photographic beam path (16),the beam splitter system (1) is again guided back into the initialposition--the glass cube (1a) therefore in the working position--at thesame time the lamp (8) being switched on, the rotary mirror (11) beingpivoted into the measurement beam path (10), the dark flaps (9 and 12,respectively) being switched out, and the image recording medium beingfurther transported.
 16. The process as claimed in claim 15, wherein thetemporal sequence of the partial process steps (c1) to (c4) is asequence selectable at will.